Sand

Sand is a naturally occurring granular material composed of finely divided rocks and mineral particles. It is defined by size being finer than gravel and coarser than silt. The composition of sand varies, depending on the local rock sources and conditions.

Manufactured sand is mainly used in the construction industry.

The increasing insufficiencies of natural sands make manufactured sands more and more important. Sand is also used to provide bulk strength and other properties to construction materials like asphalt and concrete.

There is a wide range of raw materials to make manufactured sands like common stone from mountains and pebbles from riverbeds.

Sand is mined in a moist or wet condition by open pit excavation or by dredging.Open pit excavation is carried out with power shovels, draglines, front-end loaders and buckle wheel excavators.

After mining, the sand material is transported to the processing plant by suction pumps, earthmovers, belt conveyors or other means.

The processing of sand for a specific market involves the use of different combinations of washers, screens and classifications to segregate particle sizes and crushers to reduce oversized materials.

Process For Manufactured Sand:

After the sand is transported to the processing plant:

• The wet sand is stock piled or emptied into a hoper, typically covered with a “grizzly” of parallel bars to screen out large cobbles and boulders.

• From the hopper, the material is transported to fixed or vibrating scalping screens by gravity, belt conveyors, hydraulic pump or bucket elevators

• Rotating trommel screen with water sprays are also used toprocess and wash wet sand

• The sand is freed from clay and organic impurities by log washers or rotary scrubbers

• After scrubbing, the sand typically is sized by water classification

• After classification, the sand is dewatered using screws, separators, cones or hydro-separators

• Once processed, the sand is transported to stockpiles by belt conveyors, or buck elevators.

Industrial sand is a term applied to high purity silica sand products with Closely controlled sizing.

Industrial sand plays a critical role in the production of a wide variety of ferrous and non-ferrous metals.

For metal production, silica sand operates as a flux to:

• Lower the melting point and viscosity of slags to make them more reactive and efficient

• Lump silica is used alone or in conjunction with lime to achieve the desired base/acid ratio required for purification

• Base metals can be further refined and modified with other ingredients to achieve specific properties such as high strength corrosion resistance or electrical conductivity

• Ferroalloys are essential to speciality steel production

• Industrial sand is used by the steel and foundry industries for de-oxidation and grain refinement

Sand is a natural material that consists of very small parts of decomposed corals, shells and rocks. The main use of sand is to provide strength to materials such as concrete or asphalt. Sand also finds its purpose:

- In landscaping, as a decorative material

- In the process of producing glasses

- As molding material for metal casting

- For making sandpaper and

- As abrasive in sandblasting.

There are 5 main processes in the preparation of sand:

1. Natural decomposition

2. Extraction

3. Sorting

4. Washing and

5. Crushing.

Natural decomposition begins when natural mechanical forces, like glacier movement, water expansion in cracks during freezing, break the solid rock into chunks, and this is quite a long process. The rock chunks will further break and become grains, due to the chemical action of rain and plants as well as from water and wind, that will carry them around and cause them to become even smaller particles.

The extraction of sand can be done on the river banks with, from under water, and from deserts. If the sand is extracted from r

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